Tuning by pruning: exploiting disorder for global response and the principle of bond-level independence

TL;DR

This paper introduces a method to tune the mechanical properties of disordered solids by selectively removing bonds, leveraging bond-level independence to achieve extreme responses like incompressibility or auxetic behavior.

Contribution

It demonstrates a simple, experimentally relevant bond removal procedure exploiting bond independence to precisely control the elastic properties of disordered materials.

Findings

Disordered networks can be tuned to extreme mechanical limits with minimal bond removal.

Bond-level responses are nearly uncorrelated, enabling targeted property design.

The approach is simple and applicable to real materials.

Abstract

We exploit the intrinsic difference between disordered and crystalline solids to create systems with unusual and exquisitely tuned mechanical properties. To demonstrate the power of this approach, we design materials that are either virtually incompressible or completely auxetic. Disordered networks can be efficiently driven to these extreme limits by removing a very small fraction of bonds via a selected-bond removal procedure that is both simple and experimentally relevant. The procedure relies on the nearly complete absence of any correlation between the contributions of an individual bond to different elastic moduli. A new principle unique to disordered solids underlies this lack of correlation: independence of bond-level response.